You can access your email while away from your computer by going to http://mail.yourdomain.co.nz/webmail. You will be presented with a few options, Roundcube (red), Nutsmail (blue) being the main ones. Each option will log you in and you will see the same email, they are just laid out differently. Roundcube is more simple, and Nutsmail is slightly newer and has a few more options, if in doubt use Nutsmail.

Log in using your username (generally your full email address) and password, any mail that has not been downloaded by your computer will be listed here. You can read, reply, and delete messages using webmail.